Electron discharge device



Sept. 14, 1937. A. MAVRQGENIS 2,092,769

ELEQTRON DISCHARGE DEVICE Filed May 17, 1929 2 Sheets-Sheet 1 a /0 a 9 m I an. Inn

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Sept. l4, 1937.

A.* MAVROGEN|S ELECTRON DISCHARGE DEVICE 2 Sheets-Sheet 2 Filed May 17, 1929 Patented Sept. 14, 1937 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE DEVICE Application May 17, 1929, Serial No. 363,833

24 Claims.

This invention relates to electron discharge devices having at least a cathode, an anode, a con.- trol electrode or control grid, and an auxiliary grid or auxiliary element, or screening grid or screening electrode, or screen grid or screen electrode, or a grid-like element, or a shielding or screening element, as well as to circuit connections and means for energizing one or more of the elements or electrodes of such electron discharge devices from electric power supply means or source.

The auxiliary grid or electrode is mounted either between the control grid and the filament or cathode or between the anode and the control grid. In the first arrangement, the auxiliary grid is used mainly to reduce the space charge surrounding the filament or cathode by drawing electrons out of this space as fast as they are emitted from the filament or cathode, thereby obtaining a condition approximating saturation. Such device may be used in radio work as a detector, amplifier, current limiting device or other device of this general type.

In the second arrangement, the auxiliary grid or electrode may be used in some particular cases if so desired as an auxiliary anode, receiving electrons emitted from the main anode, which latter is bombarded by electrons received from the main cathode. Under these conditions the device acts as a negative resistance and may be used as an amplifier, as a generator of continuous high frequency oscillations, or as a modulator. In this case the auxiliary grid is usually maintained more positive or at a higher positive voltage than the main anode with respect to the main cathode.

In the first arrangement where the auxiliary grid or electrode is mounted between the cathode and the main grid, and in the second arrangement where the auxiliary grid is mounted between the control grid and the anode, the voltage difference between the cathode and the auxiliary grid. in each instance, may be of any desired value with reference to the voltage difference between the anode and the cathode.

In the second arrangement, where the auxiliary grid. or electrode is located or mounted between. the control grid and the anode, it acts in a capacity to reduce, or counterbalance the electrostatic field between the main anode and the control grid, the field being due to the interelectrodal capacity of the electron discharge device.

Such device, therefore, may be used in radio work as an amplifier in which a higher voltage amplification may be secured under some conditions without the presence of oscillation.

These devices become very unstable in use and need close care and frequent adjustment in order to maintain them in an operative condition. If 5 it isattempted to energize the filament by alternating current it has been found that such devices are not capable of satisfactory operation under any condition. They are so unstable that they immediately go into undesirable oscillations 10 and fail wholly to operate in their desired capacity. From the fact that the field produced in. the tube is pulsating or variable, due to the variation in electron emissive power of the filament with the alternating heating from the alternat- 15 ing current, it is apparent that a hum and a material unsettling of the conditions will result. Further than this, the filament has a variable magnetic field about it which alternates in step with the current and, consequently, produces a 20 further pronounced disturbance. In addition to these effects, the filament does not have all portions at the same potential when alternating current is used and consequently a further varying and disturbing effect is produced.

All of these conditions or efiects are superimposed or added, one to the other, so that a highly unstable condition obtains and one which immediately throws the tube into undesirable oscillations so that it cannot operate in the ca- 30 pacity intended.

Objects of this invention are to provide means whereby the defects mentioned above are eliminated and to provide a device in which a cathode and anode and a plurality of interposed grids 35 are employed, one of these grids being a control grid, another of these grids being a screen grid adapted to be furnished with a constant potential from an alternating current source.

Another object of the invention is to provide means, in a screen grid tube, which means permits the use of alternating current for cathode heating purposes without any disturbing effect on the screening element or grid.

A further object of the invention is to provide means, in a screen grid tube, which means electromagnetically or electrostatically shields or screens the screen grid from the cathode heating means.

Another object of the invention is to provide a screen grid tube having an additional outer grid-like screening member, which may be connected with the screen grid proper or with any other suitable element of the tube.

Another object of the invention is to provide a screen grid tube in which the screening grid or grid-like element is connected to the cathode or other element or electrode of the tube.

Further objects are to provide an electron discharge device having a cathode, a plurality of electrically dissimilar electrodes, one of which acts as a screen electrode, and an anode, in which either or both the screen electrode and the oathode are adapted to be supplied from alternating current source, although no unstable condition obtains.

Another object of the invention is to operate screen grid tubes on alternating current and to provide circuits therefor for such purpose.

A further object of the invention is to provide means for supplying a proper potential to the screening grid or to the outer anode screening member of a tube from an alternating current source, such means being located either outside or inside the tube.

Another object of the invention is to provide different potentials for the screen grid and the anode of the tube.

A further object of the invention is to provide a screen grid tube suitable for either alternating or direct current operation.

A further object of the invention is to provide appropriate circuits as well as means for energizing a screen grid tube from either an alternating or a direct current source.

A further object of the invention is to provide radio circuits and means for supplying one or more electrodes or elements of a screen grid tube from a source of current through a rectifier having a cathode which may be a directly heatable filament or an indirectly heated element, or both.

1 Another object of the invention is to provide a screen grid tube having an outer screening or shielding member or element which may be substantially mechanically separate and distinct from the inside of the wall of the receptacle or envelope of such tube.

Further objects are to provide a device of the character outlined above, which is provided with a reduced number of terminals, although a plurality of electrically dissimilar grids, elements or members are provided, which is extremely stable in operation and in which the cathode activating means is itself adapted to be energized from alternati'ng current.

Further objects are to provide an electron discharge device including rectifying and signal responsive means in which one or more of the parts are energized from alternating current, in

which there is no hum or other disturbance present, in which a screen or shield grid is provided and maintained at a' fixed potential, which is positive with respect to the cathode of the device.

A further object of the invention is to provide an electron discharge device having an equipotential or indirectly heated cathode, cathode heating means or a heater therefor, an anode and two interposed electrodes, one of which is an 7 electron controlling electrode, and the other of '5 which is a screen electrode.

Another object of the invention is to provide circuit connections including power supply means for energizing one or more of the elements of an electron discharge device provided with a screen 7 grid, such, for instance, as has been outlined immediately above.

Further objects of the invention will appear as the description proceeds.

I Embodiments of the invention are shown in the 7'5 accompanying drawings, in which:

Figure 1 is a diagrammatic view showing one form of the invention.

Figure 2 is a similar View, showing a further form of the invention.

Figure 3 is a view showing a further form of the invention.

Figure 4 is a diagrammatic view showing a form of the invention in which the cathode of the signal responsive device has a double duty and acts not only as a cathode, but also as an anode for the rectifier.

Figure 5 is a view showing a form of the invention, in which the rectifier is mounted within the vessel or envelope enclosing the signal responsive device.

Figure 6 is a View similar to Figure 5 showing a further form of the invention.

Figure 7 is a modified form of the invention, somewhat similar to Figure 4;, but showing a difierent arrangement of the elements.

Figure 8 is a view, somewhat similar to Figure 7, showing a further form.

Referring to the drawings, particularly Figure 1, it will be seen that an evacuated vessel or envelope l encloses an equipotential or indirectly heated cathode 2, an anode 3, a control grid l and a screen grid 5. The screen grid is inter posed between the control grid and the anode and if desired, have a portion located beyond the anode in order to shield the anode from the control grid 4 as well as from possible external disturbances. The equipotential or indirectly heated cathode is heated in any desired manner as by means of the filament 6.

A rectifier Z is provided with an anode 8 and a cathode 9. The rectifier is supplied. from an alternating current source as, for instance, by

means of the secondary iii of a transformer. The cathode of the rectifier is connected through smoothing means, including a choke coil H and condensers i2 and E3, to one end of a resistance It. The other end of the resistance is connected to the negative side of the condensers l2 and i3 and to the equipotential or indirectly heated cathode 2. The positive sides of the condensers are connected to opposite ends of the choke coil H. The smoothing means, consisting of the choke coil and condensers, is connected to one end of the output coil or primary I5, the other end of this primary is connected to the anode 3 of the signal responsive device. If desired, the smoothing means may be connected through a portion of the resistance M to the output coil it as it is clear, as indicated in Figure 1, that the. lower point of the coil or primary iii may be con-- nected to a selected point of the resistance it. Further, it is obvious that a resistance may be placed in series with the anode, if desired.

The screen grid 5 may have any desired volt-- age impressed thereon by connecting it to a selected point of the resistance M, as shown in Figure 1. It is obvious, also, that the screen grid can be connected through a series resistance to the smoothing means, instead of a parallel resistance,.or both through a parallel resistance and a series resistance as shown in Figure 6 hereinafter described.

In the form of the invention shown in Figure 1, separate secondaries I6 and l! are provided for the filaments 6 and 9 of the signal responsive device and of the rectifier, respectively.

Referring to Figure 1, as well as to other figures of the drawings hereafter described, it will be seen that the anode 3, as shown diagrammatically, is enclosed or surrounded by the electrostatic shielding or screening means 5 and 5'. In other words, this anode 3 may be located, as shown diagrammatically, between a plurality of screening or shielding portions, members or elements which may be similar or dissimilar in structure, and which are placed opposite toa plurality of surfaces or sides of the anode 3 and spaced therefrom. Therefore these shielding or screening means are adapted to substantially intercept the electrostatic lines of force extending between the inner and outer sides or surfaces of the anode and some one or more of the elements of the device, such as the control electrode or grid 4, whereby the capacity between the anode 3 and the control electrode 4 or the capacitive coupling thereof is materially reduced or practically obviated.

Referring again to Figure 1, as well as to other figures hereinafter described, it will be seen that a plurality of means, given for illustrative purposes, are provided in the system which enable the screen grid of the tube to be supplied at any suitable positive potential varying from that supplied to the anode or to the anode circuit down to the potential of the cathode, as a variable connection has been illustrated. Obviously, different types of screen grid tubes require different voltages for the screen grid, but this invention provides any desired voltage for the needs of any particular type of tube to thereby secure the maximum efficiency.

The input circuit may take any form desired, for instance, as shown in Figure 1, the secondary H! of the input transformer may be connected at opposite ends to the equipotential or indirectly heated cathode 2 and the electron control grid 4. It is to be noted also from reference to Figure 1 that the equipotential or indirectly heated cathode is connected to one end of the secondary I!) of the transformer, the other end of such secondary being connected to the anode 8 of the rectifier.

It is to be appreciated that the smoothing means may be enclosed within the base of the tube, if desired, or may be entirely separate therefrom without departing from the spirit of this invention.

From the description of the first form of the invention, it is apparent that the defects heretofore existing in screen grid tubes, which preclude their use when the parts are energized from alternating current, are entirely eliminated by this invention. For example, the electrostatic disturbance between the filament and the anode of the screen grid tube is wholly eliminated as the voltage difference between the anode and the equipotential or indirectly heated cathode does not fluctuate with the alternating heating current. A second defect, which exists with the former types of screen tubes, is eliminated by this invention. as the alternating electromagnetic field produced by the alternating current flowing in the filament does not manifest itself in the space outside the cathode. Instead, the equipotential or indirectly heated cathode prevents any disturbing effect from being produced by this electromagnetic field.

Referring to Fig. 1, for example, it will immediately be seen that the electron-emitting ele ment 2 is interposed between the heater 6 and the screen grid 5. By this arrangement the element or cathode 2 is well adapted to substantially electrostatically or electromagnetically screen or shield the heater 6 from the screen grid. It is obvious that this arrangement permits the utilization of a variable or alternating current for producing the electronic emission required for the operation of the device without any appreciable disturbing effect on the operating characteristics of the vacuum tube.

A further defect existing in screen grid tubes, as heretofore constructed, is overcome by this invention. In the screen grid tubes as heretofore made, a very unstable condition existed which precluded the use of the screen grid tubes with alternating current. It will be appreciated immediately that the great amplification secured by screen grid tubes has the inherent tendency to produce undesirable oscillations unless conditions are maintained stable within the tube. Obviously, when the filaments of screen grid tubes, as heretofore constructed, were energized by alternating current, a wholly inoperative arrangement resulted, as the different portions of the filament had different voltages and, consequently, an unsettling condition was produced which immediately unbalanced the tube and threw this system into undesirable oscillation, thus rendering it impractical. In addition to this, the electron emissive power of the filament fluctuated, with each fluctuation of the current thus producing a further unstable effect.

With this invention, the great amplification secured by screen grid tubes is made possible even when the tube is energized from an alternating current source. This has not heretofore been possible, but due to the fact that the conditions within the tube, that is to say, the electrostatic and the electromagnetic fields are not allowed to manifest themselves in the space outside the cathode, nor is there any fluctuation whatsoever in the voltage at different points in the equipoi tential or indirectly heated cathode, but instead. a uniform voltage difference is maintained between the anode and the cathode so that the maximum stability is obtained thereby, permitting the adjustment for large amplification with the certainty of a stable operation of the device.

The invention may take other forms, for ex ample, as shown in Figure 2, the smoothing means may be placed within the base I of the tube. The evacuated portion I may enclose the same parts as those described in connection with Figure 1. Further, the smoothing means may consist of a condenser l9 bridged by a resistance 20. The tube is supplied by means of a rectifier 1, similar to that previously described. The equipotential or indirectly heated cathode 2 of the signal responsive device may be connected to one of the leads from the filament 6 and this lead may be connected both to the secondaries l6 and Ill. The input and output circuits are indicated as in Figure 1. The screen grid 5 is connected to an intermediate point, or selected point, of the resistance 20. In fact, means are provided for maintaining the screen grid 5 as well as the outer screen member 5 at any suitable potential.

Referring again to Figure'2, it will be seen that the grid-like element interposed between the control grid 4 and the anode 3 or the screen grid 5 is electrically connected within the vacuum tube itself to other elements of the device such as to the cathode 2 and to the filament 6. Further, in the form shown, the outer shielding or screening portion or member 5 is electrically connected to the cathode 2 and to the filament 6 Within the envelope of the device, whereby it is adapted to be maintained in operation at substantially constant potential. Furthermore, this form of vacuum tube requires a less number of tube terminals than the form of device shown in Figure l, for example.

It is obvious that either form, or in fact other forms, of smoothing means could be employed with either of the forms of invention shown in the Figures 1 and 2.

Figure 3 shows a form of the invention in which the smoothing means, similar to that shown in Figure 2, is located within the base I of the tube, although obviously it might be located outside, if desired. The smoothing means is similar to that described in connection with Figure 2. However, the screen grid 2| is. located between the control grid 22 and the cathode 2 and it is adapted to be maintained at any suitable potential in the form shown.

Otherwise, this form of the invention is similar to that shown in Figure 2.

Referring again to Figure 3, as well as to Figure 4, hereinafter described, it will be seen that the grid-like element, or the space charge grid, or the screen grid 2| interposed between the cathode and the control electrode or grid 22 is electrically connected to the cathode 2, as well as to the filament ii in the form shown in Figure 3, Within the envelope of the vacuum tube, whereby this element or grid 2| is adapted to be maintained in operation, at substantially constant or fixed potential. Further, the grid-like element or screen grid 2 l, which is shown located between the control grid 22 and the cathode 2 and which is thereby enabled to modify the electronic or electrostatic field between the cathode and this control grid or the anode 3, is adapted to be maintained at any suitable potential within the range extending from that supplied from the rectifier or power supply means down to the lowest potential of the cathode or of the power supply means as clearly shown in Figure 3 and Figure 4 by the conventional variable or adjustable connection given for illustrative purposes; whereby this gridlike element 2i is adapted to suit any particular condition.

In the form of the invention shown in Figure l, the screen grid has been shown as arranged in Figure 3 and previously described, although obviously it could be arranged as shown in Figures 1 and 2. The invention shown in Figure 4, however, differs from that previously described in that the equipotential or indirectly heated cathode 2 serves as the anode of a rectifier, the oathode of such rectifier being the filament 6. The smoothing means in this form of the invention may be similar to any of the forms previously described, or it may consist of a resistance 23 and condensers 2d and 25, the condenser having in each instance one end connected to an end of the resistance 23. The resistance 23 takes the place of the choke coil II, as illustrated in Fig ure 1. Otherwise, the smothing means functions in the same manner as that previously described and it may be located either inside the structure of the device as shown in Figure 4 or outside as shown in Figure 1.

The tube may be energized from an alternating current source, for instance, from a single secondary 26. A portion of the secondary is employed for energizing the filament and a portion for supplying current to the anode and the screen grid.

It is to be noted, however, that other arrangements of secondaries could be employed, if desired, without departing from the spirit of this invention.

It is to be noted in this form of the invention that the anode of the signal responsive means or signal responsive portion is supplied with energy from the rectifying means, rectifying portion or rectifier consisting of the filament 6 and the cathode 2 (which functions as the anode of the rectifier), the current, of course, passing through the smoothing means.

In the form of the invention shown in Figure 5, the same general type of signal responsive means has been shown as that previously described in connection with Figure 1. However, the rectifier in this form of the invention is mounted within the evacuated portion of the tube. Preferably the rectifier consists of an equipotential or indirectly heated cathode 21, a heater or filament 28 therefor and an anode 29. The device is supplied from an alternating current source, for instance, from the secondary Ell of a transformer. One end of this secondary may be connected to the anode 29 of the rectifier. The cathode of the rectifier is connected to the smoothing means consisting of the condenser 32 bridged around a resistance 3!. The cathode of the rectifier is connected to one end of the primary l5 of the output circuit, the other end of such primary being connected to the anode 3 of the signal responsive means. The equipotential or indirectly heated cathode 2 of the signal responsive means is connected to one side of the filament 6. The filaments 6 and 28 may, if desired, be connected in series and may be energized from the secondary 35 of the transformer.

Referring again to Figure 5, as well as to Figure 1, Figure 2 and to other figures hereinafter described, it will be immediately seen that the grid-like element, or screen electrode 5, which is shown located between the anode 3 and the control grid 4 and which serves to modify the electronic or electrostatic field surrounding the said control grid or extending between this anode and said control grid, in other words to substantially intercept the lines of electron flow or the electrostatic lines of force extending from this anode 3, is well adapted to be maintained at any suitable potential within the range extending from that supplied from the rectifier or power supply means or from that supplied to the output circuit of this device or to this anode 3, down to the lowest potential of the cathode or of the power supply means, as clearly shown by the conventional variable or adjustable connection given for illustrative purposes; whereby this grid-like element is adapted to suit any particular condition. Further, in connection with Figure 5 as well as Figure 2 and other figures hereinafter described, this grid-like element or electrode 5 is electrically connected within the device itself to the cathode 2, which is a part, or a point in this device of a substantially fixed or constant potential, whereby this grid-like element or screen electrode 5 is adapted to be maintained, in operation, at substantially fixed or constant potential. Furthermore, this arrangement of the cooperating elements or electrodes of this device makes it possible to provide a vacuum tube having a reduced number of terminals or prongs.

In the forms of the invention shown and described, it is intended that the alternating current source be construed as any alternating current source. For instance, this alternating current source may be either directly from the mains, as will be described hereinafter, or may be from a secondary of a transformer connected with the supply mains. It is intended primarily that these devices be energized from alternating current industrial supply mains, when the use of storage or dry batteries or accumulators is not desired and they, obviously, may be either di rectly supplied therefrom or may be supplied therefrom through a transformer or any other device.

As shown in Figure 6, the filaments and the entire device, in fact, may be directly supplied from the industrial alternating or direct current mains 33. One side of the mains is connected to the anode 29 of the rectifier, the other side of the mains may be connected through a rheostat 34 to the smoothing means and to one side of the filaments 6 and 28, the other side of thefilaments device.

being connected to the anode 29 of the rectifier and, consequently, to the other main. The smoothing means or filter may take any form, for instance, it may have a resistance 35 associated with condensers 36 and 31, as previously described. The indirectly heated cathode ll of the rectifier is connected to one side of the smoothing means and the smoothing means is connected to the anode 3 of the signal responsive A resistance 38 is bridged around the smoothing means and a selected point thereof is connected to the screen grid 5. The input circuit may include the secondary l8 of the input transformer, whose ends are connected to the equipotential or indirectly heated cathode 2 of the signal responsive device and to the control grid. The cathode 2 of the signal responsive device is connected to the output circuit, for instance, the primary |5 of an output transformer. The other end of this output transformer is connected to the smoothing means and thus the circuit is completed. As shown in Fig. 6, the screen grid tube and the circuits therefor are well adapted to be energized from a source of either alternating current or direct current such as the city mains 33. Also, as shown in Fig. 6, the filament or cathode heating means 28 of the rectifier and the filament or heater 6 of the screen grid device are arranged in the same circuit with the resistance 34 and supplied in series from the alternating or direct current mains 33.

In the form of the invention shown in Figure '7, the cathode 2 of the signal responsive device performs a double duty, as it acts not only as cathode for the signal responsive device, but also as the anode of the rectifier, the cathode of the rectifier being the filament 6. This construction, as thus far described, is similar to that shown in Figure 4. The smoothing means may be located in a tube base adaptor as indicated in dotted line by the reference character 38 or it may be located in any position desired. The smoothing means may take any form, for example, it may consist of a coke coil 39 and condensers 40 and ll. A resistance 42 is bridged around the smoothing means and an intermediate point .75 of the invention may be located either in the base of the tube or outside of the tube at any position desired.

Obviously, the smoothing means may take any form, for instance, it may consist of a condenser 43 bridged by a resistance 44, an intermediate point of which is connected to the screen grid 5. The device, similar to that shown in Figure 7, may be supplied from the secondary 45 of a transformer, a similar arrangement being shown in Figure '7. The filament 6 in Figures '7 and 8 may lie supplied from a portion of the secondary 45.

Further, it is apparent that the features shown in the different figures of the drawings are to be considered as interchangeable, or in other words, a feature or features shown in one figure may be used in the form of the invention shown in other figures, in accordance with the usual practice in interpreting the disclosures of an invention. Obviously, it is not necessary that all the elements or features shown in the various figures should be present in every instance. For example, the smoothing means shown at I9 in Fig. 2 may be interchanged with the smoothing means ll, l2, and I3 of Fig. l; the smoothing means ll-l3 of Fig. 1 may be contained in a vessel as shown in Fig. '7; the form of screen grid shown at 2| in Figs, 3 and 4 may be changed to the form shown in Figs. 1 and 2, or vice-versa, if so desired. Similar remarks apply to the remaining figures, and therefore the invention is not to be limited to what is specifically illustrated but only by the appended claims.

It is to be understood that the equipotential or indirectly heated cathodes in all forms of the invention are preferably coated, or otherwise associated, with a thermionic oxide so that they will emit electrons at a relatively low temperature, although, obviously, the spirit of the invention will not be departed from if plain uncoated equipotential or indirectly heated cathodes are employed.

It is to be noted, also, that the alternating current source in each instance is intended primariiy to be the industrial alternating current supply mains, whether connected to the tube through a transformer or any other device or whether connected directly to the tube. It will be noted that provision has been made in this invention for a complete and entire elimination of all batteries if so desired and that the entire device may be energized from alternating current with the assurance that a stable, satisfactory and reliable condition of operation will be maintained at all times. While the electron discharge device described above, as well as the circuit connections therefor, are suitable for alternating current operation, nevertheless it is well understood that the invention is not to be limited to the use of alternating current for wholly or partially energizing this device, but that at least one form of the invention, namely that shown in Figure 6, will operate also with direct or fluctuating current as well as with alternating current, and that at least certain forms of the tube per se, outlined above, are adapted to operate with alternating current, as well as with direct current.

By the use of this invention it is possible to utilize the high amplification power of screen grid tubes and energize these tubes with alternating current, which prior to this invention has never before been possible, as the unstable and unsettling conditions noted above have always heretofore been present. This invention, however, eliminates or overcomes all of these unstable or unsettling conditions and insures, as

stated, a smooth, uniform, stable and reliable operation of the device.

In the embodiment of Fig. 6 the screen grid is so connected to the load circuit that the potential between the screen grid and cathode fluctuates similarly in phase to the fluctuations of potential between the anode and cathode. That is, the screen grid voltage has an alternating component of similar phase to the alternating component of the anode voltage.

Although the equipotential or indirectly heated cathode has been shown as a cap-like member in the diagrammatic showing, it may take any form desired.

The tube outlined in this invention may be used as a radio frequency or audio frequency amplifier, or as a detector, and may be used in wireless work or in telephony.

It is to be distinctly understood that the screen grid may take any form desired, for example, it

may be formed of wire mesh, a helix, or an apertured member. However, when a screen grid is employed having a portion located outside of, or beyond, the anode of the signal responsive device,

this portion may take any form, as outlined above, or it may be formed of sheet metal in the form of a cylinder or any other shape. The anode, as well as the control grid, may surround the cathode, While the screen grid or grid-like electrode may surround the control grid as one possible physical form of the invention.

It is to be clearly understood, that the drawings disclose only a few embodiments of the invention, given merely for illustrative purposes,

5' that the invention may be variously embodied,

that, obviously, the shape and sizes of the different elements or parts, the location of the leads, the number of elements supplied from the same power source, and other features may be varied to suit any particular demand, and that various changes or modifications both in the device and in the circuits therefor are contemplated and are to be considered as being within the scope and spirit of the appended claims.

5 I claim:

1. The combination of an electron discharge device including a vessel inclosing an indirectly heated cathode, means for heating said cathode, an anode designed to receive electrons from said 50 cathode, a plurality of electrically dissimilar electrodes placed successively after said cathode, one of said dissimilar electrodes being an electron controlling electrode interposed between said anode and said cathode, another of said dissimilar electrodes being a screen electrode located between said controlling electrode and said anode, and an outer electrostatic shielding element electrically connected within said device to said screen electrode and substantially mechanically separate and distinct from the inner wall side of said vessel; a source of alternating current; rectifying means for supplying said anode and for impressing a positive potential upon said screen electrode with reference to said cathode; and means for maintaining said anode at a positive potential different from that of said screen electrode with reference to said cathode from said source of alternating current.

2. The combination of an electron discharge 70 device adapted to serve both as an operating current rectifier and as a signal responsive device, said electron discharge device including an indirectly heated cathode, means for heating said cathode, an anode designed to receive electrons 75 from said cathode, and a plurality of electrically dissimilar grids successively placed after said cathode, one of said dissimilar grids being a control grid, another of said dissimilar grids being a screen grid interposed between said anode and said control grid; and'means for maintaining at least said screen grid positive with reference to said cathode.

3. The combination of an electron discharge device adapted to serve both as an operating current rectifier and as a signal responsive device, said electron discharge device including an indirectly heated cathode, an anode designed to receive electrons from said cathode, a plurality of electrically dissimilar electrodes placed successively after said cathode, one of said dissimilar electrodes being an electron controlling electrode and being interposed between said anode and said cathode, another of said dissimilar electrodes being a screen electrode, and an outer screening member for substantially screening an outer surface of said anode from said controlling electrode; an alternating current source; and means including smoothing means for impressing a positive voltage at least on said screen electrode with reference to said cathode from said alternating current source.

4. The combination of an electron discharge device comprising a vessel; operating current rectifying means and amplifying means enclosed within said vessel; said amplifying means hav ing an indirectly heated cathode, an anode cooperating with said cathode, and a plurality of electrically dissimilar electrodes placed successively after said cathode, one of said dissimilar electrodes being an electron controlling grid, another of said dissimilar electrodes being a screen electrode located between said anode and said controlling grid; a source of alternating current; and means including smoothing means connected to said rectifying means and at least to said screen electrode for impressing a positive voltage on said screen electrode with reference to said cathode from said source of alternating current.

5. An electron discharge device comprising an envelope; a plurality of cooperating elements enclosed within said envelope, said elements including an indirectly heated cathode, an anode designed to receive electrons from said cathode, and a plurality of electrically dissimilar grids placed successively after said indirectly heated cathode, one of said grids being a control electrode, another of said grids being a screen electrode located between said cathode and said anode, and means for heating said cathode; and means for impressing a positive voltage on said screen electrode with reference to said cathode and forming with said envelope a unitary structure.

6. An electron discharge device comprising an envelope; a signal responsive portion and a rectifying portion, both said portions being enclosed within said envelope, said signal responsive portion including a cathode, an anode designed to receive electrons from said cathode, and a plurality of electrically dissimilar elements successively placed after said cathode, one of said dissimilar elements being an electron controlling electrode interposed between said cathode and said anode, another of said dissimilar elements being a screen electrode positioned between said cathode and said anode; said rectifying portion being designed to supply in operation a positive voltage at least to said screen electrode with reference to said cathode.

, '7. An electron discharge device comprising an evacuated vessel; a plurality of cooperating elements enclosed within said vessel, said elements including a cathode, an anode designed to receive electrons from said cathode, a plurality of elec trically dissimilar electrodes successively placed after said cathode, one of said dissimilar electrodes being a control electrode, another of said dissimilar electrodes being a screen electrode located between said anode and said control elec- 1o trode, and an outer screening element for substantially screening a surface of said anode and being electrically connected to one of the elements of said device; and means for impressing a positive potential on at least said screen electrode with reference to said cathode, said means forming with said device a unitary structure.

8, An electron discharge device comprising an envelope having an evacuated portion; rectifying means and signal responsive means both enclosed within said evacuated portion; said signal responsive means including a cathode, an anode designed to receve electrons from said cathode, a plurality of electrically dissimilar grids placed successively after said cathode, one of said grids being a control grid, another of said grids being a screen grid; said rectifying means being adapted to supply at least one element of said signal responsive means; and means carried by and forming a part of said device for impressing a rectified positive voltage on at least said screen grid with having a cathode, an anode, an electron controlling grid, and a screen grid; rectifying means enclosed within said vessel for supplying potential to said amplifying means; and a resistance connected to said rectifying means and to said screen grid for maintaining said screen grid at a positive voltage with respect to said cathode; said resistance being located within said base.

10. The combination of an electron discharge device having an envelope, an electron emitting '4 cathode, an anode designed to receive electrons from said cathode and having a plurality of surfaces, a control electrode for controlling the electron flow between said cathode and said anode, all said electrodes being provided with leads 50 and being enclosed within said envelope, a screening electrode positioned between said anode and said cathode, and a grid-like element enclosed within said envelope and being located opposite to at least one of said anode surfaces for substantially screening at least one of said anode surfaces and being electrically connected within said device to said cathode, whereby said gridlike element is maintained in operation at substantially fixed potential, an alternating current 60 source, circuit connections for supplying cathode heating current to said device from said source, and a plurality of means including rectifying and smoothing means for impressing a positive potential to said anode and for maintaining said 65 screening electrode positive with reference to said cathode from said source.

11. The combination of an electron discharge device having a plurality of cooperating elements including an electron emitting cathode adapted 70 to be energized by an electric current, an anode,

a control electrode, a screen electrode interposed between said anode and said control electrode, and an outer grid-like shielding element electrically connected within said device to at least one 75 of the elements of said device other than said control electrode; an alternating current source and means including current converting means for applying a positive potential on at least said screen electrode with reference to said cathode from said alternating current source.

12. An electron discharge device adapted to serve both as a signal responsive means and as rectifying means, said electron discharge device including an indirectly heated cathode, an anode, and a plurality of electrically dissimilar electrodes, one of said dissimilar electrodes being a control electrode, and another of said two dissimilar electrodes being a screen grid located be tween said anode and said control electrode, said rectifying means being designed to supply space current to said signal responsive means.

13. An electron discharge device comprising a rectifying portion and a signal responsive portion, said signal responsive portion including an indirectly heated cathode, an anode designed to receive electrons from said cathode, a plurality of electrically dissimilar electrodes successively placed after said cathode, one of said dissimilar electrodes being a control electrode interposed between said anode and said cathode, another of i said dissimilar electrodes being an inner screen electrode, and an outer shielding member for substantially shielding an anode surface from said control electrode, said rectifying portion being adapted to supply rectified positive voltage to at least the screen electrode of said signal responsive portion.

14. An electron discharge device comprising a I vessel; signal responsive means enclosed within said vessel and having a cathode adapted to emit electrons, an anode designed to receive electrons from said cathode, a control electrode for controlling the electron flow between said cathode and said anode, and a fourth grid-like electrode located between said control electrode and said anode; and means forming with said device a unitary structure for applying a potential on said fourth electrode with reference to said cathode.

15. The combination of an electron discharge device comprising a plurality of cooperating elements including an indirectly heated cathode, an anode designed to receive electrons from said cathode, cathode heating means for activating said cathode, and a plurality of electrically dissimilar electrodes successively positioned between said cathode and said anode, one of said dissimilar electrodes being a control grid, another of said dissimilar electrodes being an inner grid-like electrode located between said anode and said control electrode, said grid-like electrode and at least one of the elements of said device other than said control grid being electrically connected wholly within said device to one another; an alternating current source; means for supplying cathode heating current from said source; and means for supplying space current to said device from said source, whereby said device operates without interference from said source.

16. The combination of an electron discharge device comprising a plurality of cooperating elements including an electron emitting cathode, an anode, and a plurality of electrically dissimilar elements, one of said dissimilar elements being a control electrode, another of said dissimilar elements being a grid-like electrode located between said anode and said control electrode, said gridlike electrode and one of the elements of said device other than said control electrode being electrically connected wholly within said device to one another; an alternating current source; and

a plurality of means for supplying space current and cathode heating current to said device from said source, whereby said device operates without interference from said alternating current source.

17. The combination of an electron discharge device comprising a plurality of cooperating elements including an electron emitting cathode, an anode, and a plurality of electrically dissimilar elements, one of said dissimilar'elements being a control electrode, another of said dissimilar elements being a grid-like electrode positioned between said anode and said control electrode, said grid-like electrode and said cathode being electrically connected wholly within said device to one another; an alternating current source; an input circuit connected to said control electrode; means for supplying cathode heating current from said source; and a plurality of means including rectifying and smoothing means for supplying anode current and for maintaining a potential difference between said anode and said grid-like electrode from said source; whereby said device operates without interference from said alternating current source.

18. The combination of an electron discharge device comprising an evacuated vessel and a plurality of cooperating elements enclosed therein and including an indirectly heated cathode, means for heating said cathode, an anode, a control electrode, a screening grid between said control electrode and said anode, and a fifth gridlike element adjacent to said anode; an alter-- nating current source; means, including rectifying means, for supplying potential to a plurality of elements of said device from said source; and a connection between said grid-like element and said cathode to thereby maintain the said gridlike element at substantially fixed potential.

19. The combination of an electron discharge device comprising a cathode adapted to be heated to emit electrons, an anode, a control electrode, an inner grid-like electrode located between said control electrode and said anode, and an outer shielding member in the form of a grid; a source of alternating current; and means including rectifying means and smoothing means connected to said grid-like electrode for maintaining a voltage difierence between said grid-like electrode and said cathode from said source without interference from said source in the operation of said device.

20. The combination of an electron discharge device comprising an envelope and a plurality of cooperating elements enclosed therein and including an electron emitting cathode, an anode, a control grid, a screening grid located between said anode and said control grid, and outer screening means including a shielding member substantially mechanically separate and distinct from the inner wall side of said envelope and successively placed after said anode with reference to said cathode; a source of alternating current; and a plurality of means including rectifying and current smoothing means for supplying a potential to the anode of said device from said source and for maintaining a voltage difference between said screening grid and said cathode from said source without interference from said source in the operation of said device.

21. The combination of electron discharge device comprising a plurality of cooperating elements including an indirectly heated cathode, a heating element for heating said cathode, an anode, a control grid, an inner screening grid located between said control grid and said anode, and an outer electrostatic shielding element in the form of a grid electrically connected within said device to one of the elements of said devices other than said control grid; a source of operating electrical potential; and means for maintaining a potential difierence between at least said screening grid and said cathode from said source of potential.

22. The combination of an electron discharge device comprising a vessel and a plurality of cooperating elements enclosed therein and including an indirectly heated cathode, heating means for heating said cathode, an anode, a control electrode, an inner screen electrode positioned between said control electrode and said anode, and an outer electrostatic shielding member substantially mechanically separate and distinct from the inner wall side of said vessel and electrically connected within said device to said cathode; an electric power source; and an electrical circuit connected between said screen electrode and said cathode for applying a positive potential on said screen electrode with reference to said cathode from said power source.

23. The combination of an electron discharge device comprising a vessel and a plurality of cooperating elements enclosed therein and including an electron emitting cathode, an anode, a control grid, an inner screening grid positioned between said control grid and said anode, and an outer electrostatic screening member substantially mechanically separate and distinct from the inner wall side of said vessel and electrically connected within said device to said cathode; a source of alternating current; and means including rectifying and smoothing means connected to said inner screening grid and to said cathode for supplying a potential to said inner screening grid with reference to said cathode from said source without interference of said source of alternating current in the operation of said device.

24. The combination of an electron discharge device comprising a vessel and a plurality of cooperating elements enclosed therein and including an indirectly heated cathode, means for heating said cathode, an anode, a control electrode, an inner grid-like electrode located between said control electrode and said anode, and an outer electrostatic shielding member electrically connected within said device to said cathode and substantially mechanically separate and distinct from the inner wall side of said vessel; a source of alternating current; rectifying means and smoothing means for supplying potential to said anode and to said grid-like electrode from said source; and means including impedance for maintaining a voltage between said grid-like electrode and said cathode substantially difierent from that applied between said anode and said cathode from said source of alternating current, whereby said device operates without interference from said source of alternating current.

ARISTOTE MAVROGENIS. 

